distinguish between grammar patterns and how to remember them

Question

Suppose we take おそれがある, we can use it with either noun or a verb:

V る ＋ おそれがある
N ＋ の ＋ おそれがある

and on the other hand if we take に違いない, we can use it with everything(noun,adjective and adverb)

Plain Form Whatever ＋ に違いない must be [whatever]; (I'll)

I feel that somehow I can also construct おそれがある along with an adjective but the sentence will be grammatically wrong as it's mentioned that おそれがある can only be used with nouns and verbs.My question is, how can I remember which grammar forms I can use with noun-verb or noun-adjective-verb or only verb ?? Do I have to memorize everything or is their any logic

Answer 1

Good question! My gut was telling me an isolated adjective would not work with 恐れがある. Checking a formal definition, it indicates "fear that something unfavourable might happen":

悪いことが発生するのではないかと推測されるさまを表す語。

And I think this is the crux of it:

恐れがある is preceded by an event.

A noun or verb may readily designate an event, but an adjective would have to describe one in order to fit.

大雨{おおあめ}の恐れがあります。 There is a risk of heavy rain.

この暗号{あんごう}方法{ほうほう}は破{やぶ}られるおそれがある。 I fear this encryption method may get cracked.

交渉{こうしょう}は激{はげ}しい恐れがございます。 We fear the negociations might turn out to be heated.

Answer 2

I think you may be confused about the sentence 恐れがある.

恐れがある is comprised of two (3 if you are picky about it) parts.

恐れ + が + ある

恐れ is a noun. が is a particle to and helps us describe 'what is it about 恐れ?' which is ある.

Because 恐れ is a noun, you can attach a verb or a particle (like の and link more nouns) or an adjective to the front of it. I am not sure which source you are reading that an adjective can not be used in front of it, as that is not true. You can describe 'what kind of 恐れ?' with many adjectives/verbs.

嬉しい恐れ - a happy fear (kind of weird)

足が震える恐れ - a fear that makes my legs tremble

ケーキが食べられた恐れ - a fear that the cake has been eaten

Language can be very confusing and always has exceptions, but to the best of my knowledge the above are universal rules.

Answer 3

There seems to be no problem with using adjectives with this construct.

An example from 'A Dictionary of Advanced Japanese Grammar':

測定誤差が大きい恐れがある。
We are worried that the measurement errors may be large.